The state is spending $161 million to connect carpool lanes on the Golden State (5) and Antelope Valley (14) freeways, and will need to close lanes next week to build new flyover ramps across the busy warren of freeway lanes, overpasses and truck bypass lanes between Santa Clarita and San
Fernando.

Various lane closures, differing each night, will be imposed on the Golden State (5) Freeway at the Antelope Valley (14) Freeway interchange, and along the 5 Freeway between the 14 and the Foothill (210) Freeway interchange, said Caltrans spokeswoman Kelly Markham.

Closures will start at 7 p.m. Sunday, and are scheduled to end no later than 5 a.m. for the freeways' main lanes, and 7 a.m. for some of the lesser-used ramps, according to Caltrans. The closures will last five nights.

Up to six northbound lanes of the freeway may be closed at the Balboa Boulevard interchange starting at 11 p.m. Sunday and continuing each night through Thursday. Traffic will be detoured onto the parallel truck ramp, but that roadway is only two lanes wide and Markham said heavy traffic can be expected.

As part of the project, drivers on the westbound 210 will occasionally be unable to directly connect to the northbound 5, Markham said. Detours via the Ronald Reagan (118) Freeway will be marked.

At various other times, transition roads between the 5 and 14, and the parallel truck lanes, will have alternating closures, she said.

"We know this is the only road through the pass, so we will always have some lanes open,'' Markham said. "This has been going on for some time now, and motorists have been very patient to adjust.''

The construction point is at the "pinch point'' where all virtually all traffic between Los Angeles and its northernmost suburbs is routed through a mountain pass, and is the same location where freeway bridges collapsed and isolated the region during the 1994 Northridge earthquake.